It gives director Stephen Frears undue credit to describe Florence Foster Jenkins as an exquisite reproof of audience voyeurism. Led along by a procession of reaction shots and comedic framing, the biopic invites us to chortle at a real-life heiress’s legendarily cacophonous crooning. But it hits a sour note when Frears suddenly turns the mirror on his audience in rebuke, in effect absolving the actual enablers the film otherwise indicts.

We meet Jenkins (Meryl Streep) in 1944, as a seventy-six-year-old New York City socialite and musical benefactor. The acclaimed conductor Arturo Toscanini (John Kavanagh) and the other musical elites who frequent her Manhattan apartment all have their hands out, but somehow they are never available to attend one of Jenkins’s many invitation-only concerts.

The reason becomes clear after she hires her latest piano accompanist, Cosmé McMoon (The Big Bang Theory's Simon Helberg). Jenkins is an atrocious singer whose high-pitched assaults on Verdi, Strauss, and Mozart’s “Der Hölle Rache” are suitable for the shower but not public exhibition.

At Jenkins’s side—if not in her bed—is St. Clair Bayfield (Hugh Grant), her “common-law” partner and manager. Screenwriter Nicholas Martin conveys Bayfield vaguely, as both a devoted mate and a mooch. He’s a resolute supporter and protector, but he also enables Jenkins’s delusion that she’s an accomplished soprano worthy of accolades. He handpicks audiences for her garish recitals and pays for positive reviews in trade papers.

The film also struggles with Bayfield’s second life with his mistress, Kathleen Weatherly (Rebecca Ferguson, Mission: Impossible—Rogue Nation). There’s an early suggestion that Bayfield’s open relationship has Jenkins’s consent, a consequence of her chronic and debilitating syphilis, which she contracted from her first husband and suffered from for fifty years. But when Jenkins pays an unannounced visit to Bayfield’s party pad, we discover that his amour with Weatherly is no secret to his coterie—only to Jenkins.

Many actors would struggle playing the title character. She’s a daft elite full of delusion, yet also a lonely, sympathetic figure blessed with the resources to fashion her own life. Still, she is a victim of the era’s patriarchal strictures. It’s a tricky role that requires dramatic and comedic range—one that Streep can ably play on cruise control.

Where the screenplay fails to drill down to the core of Jenkins and Bayfield’s character contradictions, Streep and Grant pick up the slack. Even Helberg, whose character is initially presented as a mere bemused nebbish, finds shared pathos when he learns of Jenkins’s accomplished but truncated history as a child piano prodigy.

It's a tidy chamber play until Jenkins at last finds public renown and performs a climactic concert at Carnegie Hall, at which point Frears and Martin pivot in a way that betrays narrative and character complexity, not to mention audience expectations. They demand that we appreciate their subject’s perseverance and triumph without having invested us in her journey—and our feelings often run directly counter to admiration. Streep and the rest of the cast carry their tunes, but as a film, Florence Foster Jenkins never quite finds its own melody.